This is a big no-no - it should only be done by a layperson if the child was in danger of death, or they live in a remote area or something.

Under Canon 849 of the Code of Canon Law:

'Baptism, ... is validly conferred only by a washing of true [pure] water [as in not orange juice or soda pop or anything] with the proper form of words.' ['I baptise you in the name of the Father, Son and Holy Spirit'. ]

Assuming the above was done, I believe it is what is called 'illicit', but still valid and still a sacrament.

In any event th baptism must immediately be reported to the man's pastor so that the rite can be completed - the child blessed and anointed with the oils and so on - and the baptism registered for future reference (if the child wants to receive any other sacrament, such as marriage, in future they will need the baptism on the record).

I was talking to a friend who said that his brother, a lay person, baptized his own daughter. Is this valid? I thought that only priests could perform the sacraments.

If lay people can baptize their children, what is needed to make it valid?

Did he say how his brother came to be the one who did the baptism?

Unless the baptism was done in an emergency, it was illicit for the dad to do that. But, if he used water and said "I baptize you in the name of the Father and of the Son and of the Holy Spirit" it would be valid. He would then have the obligation to report it to his pastor ASAP so that it could be recorded in the parish's register of baptisms.

Unless the baptism was done in an emergency, it was illicit for the dad to do that. But, if he used water and said "I baptize you in the name of the Father and of the Son and of the Holy Spirit" it would be valid. He would then have the obligation to report it to his pastor ASAP so that it could be recorded in the parish's register of baptisms.

I don't know why he performed the baptism. I don't think that the child was in danger of death. This was about 18 years ago. The daughter is now in college.

He did have Holy Water, and I think he used the correct statement. He later told his priest that he baptized his daughter, so when he actually went to a Baptismal ceremony, the priest just mimicked the application of water and blessed the child. The priest's reasoning was that he could not baptize the child a second time, seeing as though the father baptized her already. It all seems like a big mess to me.

I don't know why he performed the baptism. I don't think that the child was in danger of death. This was about 18 years ago. The daughter is now in college.

He did have Holy Water, and I think he used the correct statement. He later told his priest that he baptized his daughter, so when he actually went to a Baptismal ceremony, the priest just mimicked the application of water and blessed the child. The priest's reasoning was that he could not baptize the child a second time, seeing as though the father baptized her already. It all seems like a big mess to me.

The priest was right not to re-baptise the child again. But there is a rite to supply the ceremonies of baptism for someone already baptised -he should have used that.

I was talking to a friend who said that his brother, a lay person, baptized his own daughter. Is this valid? I thought that only priests could perform the sacraments.

If lay people can baptize their children, what is needed to make it valid?

Anyone can Baptize anyone validly, who is not already Baptized. This is done licitly in case of necessity or danger of death. When done the Baptism must be reported to the nearest parish to be recorded in their Baptismal register and to have the additional Rites of Baptism supplied.

In the more canonically regular case of a priest or deacon with children, I believe it would be inappropriate (and perhaps outright illicit - in the Latin code - but I can't remember for sure) for him to baptize his own children because, at least in the ordinary form of the rite, this would entail him performing two roles at once (minister and parent) during the rite.